Research Article Evaluation of Antidiabetic and Antioxidant Properties of Brucea javanica Seed Abdulwali Ablat, 1 Jamaludin Mohamad, 1 Khalijah Awang, 2 Jamil A. Shilpi, 2 and Aditya Arya 3 1 Institute of Biological Science, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia 2 Department of Chemistry, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia 3 Department of Pharmacy, Faculty of Medicine, University of Malaya, 50603 Kuala Lumpur, Malaysia Correspondence should be addressed to Abdulwali Ablat; aablat@gmail.com Received 27 November 2013; Accepted 19 December 2013; Published 5 February 2014 Academic Editors: M. Elisaf and G. Yoon Copyright © 2014 Abdulwali Ablat et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Te ethanol extract of B. javanica seed was fractionated with solvents of diferent polarities and tested for antioxidant activities by several assays including DPPH radical scavenging activity, ferric reducing antioxidant power (FRAP), ferrous ion chelating activity (FCA), and nitric oxide radical scavenging activity (NORSA) along with their polyphenolic contents. Antidiabetic activity was evaluated both in vitro and in vivo using a glycogen phosphorylase  (GP) inhibition assay and oral glucose tolerance test (OGTT) in nondiabetic rats. Te ethyl acetate fraction (EAF), rich in tannin, exhibited the strongest antioxidant activities to DPPH, FRAP, and NORSA, except for FCA. Te EAF also exerted a dose-depended inhibition of GP (IC 50 = 0.75 mg/ml). Further evaluation of hypoglycemic efect on OGGT indicated that rats treated with EAF (125 mg/kg bw) showed a 39.91% decrease ( < 0.05) in blood glucose levels at 30 min, and continuous fall ( < 0.05) of 28.89% and 20.29% was observed in the following hours (60 and 90 min) compared to the normal control during OGTT. Te EAF was applied to polyamide column chromatography, and the resulting tannin-free fraction was tested for both GP inhibition and antioxidant (DPPH only) activity. Te GP inhibitory activity was retained, while antioxidant activity was lost (4.6-fold) afer tannin removal. Tese results concluded that the GP inhibitory activity initially detected was primarily due to the compounds other than tannins, whereas antioxidant activity was mainly due to the tannins. 1. Introduction Diabetes is one of the most common chronic diseases characterized by hyperglycemia as a result of impaired insulin secretion by pancreatic  cells and by cellular resistance to insulin [1]. Diabetes mellitus is recognized by the World Health Organization (WHO) as a tremendously increasing global epidemic with more than 285 million people around the world aficted in 2010 and it is estimated that the number of people with diabetes will increase to 439 million by 2030 [2]. Te current pharmacological treatment of diabetes is aimed at maintaining strict control of glycemia using oral hypoglycemic agent and insulin or combination of both. However, currently available oral antihyperglycemic agents, even when used intensively, are ofen unable to control the hyperglycemia and the disease progressively worsens with time. Oxidative stress has been suggested to be critically involved in the pathogenesis and progression of diabetes, including cardiovascular diseases [3], chronic kidney disease [4], ageing [5], and diabetes [6]. Te ethnopharmacological evidence has proven that the use of herbal medicine is a viable alternative for the control of diabetes and other diseases. Te benefcial properties of herbal medicine include signifcant efciency, fewer side efects, relative safety, and especially low cost for a patient who cannot aford precious medication [7]. In fact, the medicinal plants are important natural sources of molecules with potential antidiabetic efects. Many plant species have been reported to have hypoglycemic efect, which may act through diferent mechanisms, including inhibition of -glucosidase [8], inhibition of DPP-IV [9], and inhibition of glycogen phosphorylase and/or enhancement of insulin secretion, Hindawi Publishing Corporation e Scientific World Journal Volume 2014, Article ID 786130, 8 pages http://dx.doi.org/10.1155/2014/786130